British Prime Minister David Cameron promised Wednesday to hold a vote on whether or not Britain would stay in the European Union if he is re-elected.
The announcement brought on warnings from fellow member states and other world leaders about the economic consequences of such a move. Even the United States weighed-in.
In a phone call, President Barack Obama told Cameron that "the United States values a strong U.K. in a strong European Union," according to a report released by the White House last week.
But Cameron emphasized that his priority is not to leave the bloc but to re-negotiate the UK's relationship with EU.
The issue would then be put before the British people as a referendum with the choice to stay in or get out.
"I say to our European partners, frustrated as some of them no doubt are by Britain's attitude: work with us on this," Cameron said.
Cameron also said the legislation will be drafted before the 2015 election so that if his party wins, it can be introduced and passed quickly.
"Let us not be misled by the fallacy that a deep and workable single market requires everything to be harmonized, to hanker after some unattainable and infinitely level playing field," Cameron said. "Countries are different. They make different choices. We cannot harmonize everything."
In spite of his call for change Cameron reiterated his support of Britain staying in the EU.
"I speak as British prime minister with a positive vision for the future of the European Union. A future in which Britain wants, and should want, to play a committed and active part," Cameron said.
"There is no doubt that we are more powerful in Washington, in Beijing, in Delhi because we are a powerful player in the European Union," he said.
But change is in order Cameron argued, as he laid out a vision of a "new" EU built on five principles: competitiveness; flexibility; power flowing back to, not just away from, member states; democratic accountability; and fairness
The current "one size fits all" approach to the 27-nation EU does not work, Cameron said.
Britain has a long history of strained relations with the bloc. It is among 10 of the EU countries that chooses not to use the euro.